The present invention relates to a method for producing a linerless label which can be formed in a roll form without using a release liner for covering a pressure-sensitive adhesive layer. The label can be printed with a pattern, etc., in situ as occasion may demand. The label can be fixed by adhesion to an adherend through the pressure-sensitive adhesive layer.
Hitherto, a method of printing while unwinding a label sheet from a roll of the label sheet wherein a pressure-sensitive adhesive layer formed on a substrate to be printed is covered with a release liner has been known. As occasion may demand, various kinds of labels, such as bar-code labels or nameplate labels, can be produced by printing an ink information on a label sheet by a printer in situ and fixing by adhesion the label onto an adherend through a pressure-sensitive adhesive layer previously formed on the label sheet. In this method, a release liner covering the pressure-sensitive adhesive layer is indispensable. Without the release liner it is difficult to unwind the label sheet from the roll thereof, and also the pressure-sensitive adhesive layer adheres to inner parts of the printer, making it impossible to produce labels.
It is also necessary to release the release liner from the pressure-sensitive adhesive layer in adhering the label to an adherend. However, because the release liner is thin and soft, it is difficult to release from the pressure-sensitive adhesive layer. Further, the released release liners are discarded waste articles.
Linerless label sheets without need of a release liner covering the pressure-sensitive adhesive layer have been proposed. These include a delayed tack type, a printed type, a sandwich type or a heat-sensitive coloring type.
However, the delayed tack type has involved problems that a means heating for giving a pressure-sensitive adhesive property is required, and the delayed tack type cannot be placed under high temperature for blocking prevention, etc. The printed type has involved the problem that because this type is pre-printed, labels newly printed in situ as occasion may demand cannot be issued. The sandwich type has involved the problem that it requires a complicated printing mechanism capable of printing on both the front surface and the back surface of the label sheet. The heat-sensitive coloring type has involved problems of poor light resistance, water resistance, chemical resistance, moisture resistance, heat resistance, etc. Disappearance, oozing, blur, etc., of the information given can occur, making it difficult to read the information visually or by a bar-code reader; also this type cannot endure use in open air.
Accordingly, an object of the present invention is to provide a method for producing a label having excellent durability wherein the label can be formed in situ as occasion may demand. The method involves applying an ink, using a roll of a label sheet having attached thereto a pressure-sensitive adhesive layer in a linerless state, i.e., without having a release liner covering the pressure-sensitive adhesive layer. The label formed can be easily fixed by adhesion to an adherend through the previously attached pressure-sensitive adhesive layer.
According to the present invention, there is provided a production method for a linerless label capable of being formed in situ. The process comprises applying an ink to the back surface of a substrate of a label sheet. The sheet is formed by winding the substrate to be printed having on one surface thereof a pressure-sensitive adhesive layer in such a manner that the pressure-sensitive adhesive layer is releasably adhered to the back surface of the substrate to be printed, and cutting the label sheet thus printed into a definite length.
According to the present invention, a roll of lineress label sheet is used and a durable label can be formed in situ as occasion may demand; the label can be easily fixed by adhesion to an adherend through a pressure-sensitive adhesive layer previously attached to the label sheet. Thus, a release liner conventionally used for covering the pressure-sensitive adhesive layer of a label sheet, becomes unnecessary.